• 대한수학회지
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• 제60권3호
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• pp.587-618
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• 2023

In this paper, we consider the existence of time periodic solutions for the compressible magneto-micropolar fluids in the whole space ℝ³. In particular, we first solve the problem in a sequence of bounded domains by the topological degree theory. Then we obtain the existence of time periodic solutions in ℝ³ by a limiting process.

• Korean Journal of Mathematics
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• 제32권1호
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• pp.109-120
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• 2024

The aim of this research is to describe lacunary ∆^m-statistically convergent sequences with respect to metrics on generalised metric spaces (g-metric spaces) and to look into the fundamental characteristics of this statistical form of convergence. Also, the relationship between strong summability and lacunary ∆^m-statistical convergence in g-metric space is established at the end.

• Korean Journal of Mathematics
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• 제32권1호
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• pp.121-135
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• 2024

In this paper, we have presented rough ideal statistical convergence of sequence on neutrosophic normed spaces as a significant convergence criterion. As neutrosophication can handle partially dependent components, partially independent components and even independent components involved in real-world problems. By examining some properties related to rough ideal convergence in these spaces we have established some equivalent conditions on the set of ideal statistical limit points for rough ideal statistically convergent sequences.

• Structural Engineering and Mechanics
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• 제52권2호
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• pp.323-349
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• 2014

In this paper, linear buckling analysis of a curved sandwich beam with a flexible core is investigated. Derivation of equations for face sheets is accomplished via the classical theory of curved beam, whereas for the flexible core, the elasticity equations in polar coordinates are implemented. Employing the von-Karman type geometrical non-linearity in strain-displacement relations, nonlinear governing equations are resulted. Linear pre-buckling analysis is performed neglecting the rotation effects in pre-buckling state. Stability equations are concluded based on the adjacent equilibrium criterion. Considering the movable simply supported type of boundary conditions, suitable trigonometric solutions are adopted which satisfy the assumed edge conditions. The critical uniform load of the beam is obtained as a closed-form expression. Numerical results cover the effects of various parameters on the critical buckling load of the curved beam. It is shown that, face thickness, core thickness, core module, fiber angle of faces, stacking sequence of faces and openin angle of the beam all affect greatly on the buckling pressure of the beam and its buckled shape.

• 호남수학학술지
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• 제27권4호
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• pp.649-654
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• 2005

Given operators X and Y acting on a separable complex Hilbert space ${\mathcal{H}}$, an interpolating operator is a bounded operator A such that AX = Y. We show the following: Let $Alg{\mathcal{L}}$ be a subspace lattice acting on a separable complex Hilbert space ${\mathcal{H}}$ and let $X=(x_{ij})$ and $Y=(y_{ij})$ be operators acting on ${\mathcal{H}}$. Then the following are equivalent: (1) There exists a unitary operator $A=(a_{ij})$ in $Alg{\mathcal{L}}$ such that AX = Y. (2) There is a bounded sequence {${\alpha}_n$} in ${\mathbb{C}}$ such that ${\mid}{\alpha}_j{\mid}=1$ and $y_{ij}={\alpha}_jx_{ij}$ for $j{\in}{\mathbb{N}}$.

• 한국실내디자인학회논문집
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• 제36호
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• pp.93-101
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• 2003

The first object of this study is to clarify the newly demanded service to the visiter in the museum. And the second is to consider the spatial configuration on the layout of exhibition and the shape of exhibition room from the view points of behavior of appreciation and other methodology. The results of this study are as follows : The exhibition content and structure of Seoul Museum of History formed by a story-line according to the theme of an each zone fixed sequence in an each exhibition that we are achieved. But the layout of exhibition and the shape of exhibition consist on the other hand of the freedom selection. So the problem appeared In the difference of the exhibition content and the layout of exhibition to the behavior of appreciation. It can be said that the concept of exhibition space should be taken into account and the spatial configuration by the completed floor plan in order to satisfy the planning concepts.

• 한국항해항만학회지
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• 제27권3호
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• pp.273-282
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• 2003

This paper proposes a sensor-fusion technique where rho data sets for the previous moments are properly transformed and fused into the current data sets to enable accurate measurement, such as, distance to an obstacle and location of the service robot itself. In the conventional fusion schemes, the measurement is dependent only on the current data sets. As the results, more of sensors are required to measure a certain physical promoter or to improve the accuracy of the measurement. However, in this approach, intend of adding more sensors to the system, the temporal sequence of the data sets are stored and utilized for the measurement improvement. Theoretical basis is illustrated by examples md the effectiveness is proved through the simulation. Finally, the new space and time sensor fusion (STSF) scheme is applied to the control of a mobile robot in the indoor environment and the performance was demonstrated by the real experiments.

• Journal of Astronomy and Space Sciences
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• 제13권1호
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• pp.55-62
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• 1996

We present UBV CCD photomety of the metal-poor globular cluster M30. The data were obtained using the 40 inch telescope at Mt. Stromlo and Siding Spring Observatory (MSSSO). We used DAOPHOT CCD reduction package in order to obtain Color-Magnitude Diagram (CMD). We have derived some fundametal parameters of the globular cluster such as metal abundance ([Fe/H]), helium abundance (Y), and distance modulus (m-M) from the CMD. The derived parameters were [Fe/H]=-2.50, Y=0.28, and (m-M)=14.64. From the latter, the distance of 8.3kpc is obtained. Despite the photometric uncertainty near the main-sequence turnoff, we estimate the age of M30 to be 1.6${\pm}$3 Gyrs from the Revised Yale Isocyrones. If [O/Fe]=+0.4, this age will be reduced to 14.2${\pm}$3 Gyrs.

• 전력전자학회논문지
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• 제7권2호
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• pp.149-157
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• 2002

본 논문에서는 공간벡터 PWM(SVPWM) 인버터에서 직류단 전압을 최대로 이용하기 위한 새로운 과변조 기법을 제안한다. 제안된 기법은 영-시퀀스 신호인 옵셋 전압 주입 원리에 근거한 SVPWM의 개념을 사용하였다. 제안된 과변조 기법에서는 폴전압을 간단히 수정함으로써 과변조 영역 전반에 걸터 인버터의 출력전압을 선형적으로 제어할 수 있게 하였다. 제안된 기법은 시뮬레이션과 실험을 통하여 그 타당성을 확인하였다.

• 호남수학학술지
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• 제28권1호
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• pp.135-140
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• 2006

Given vectors x and y in a separable Hilbert space H, an interpolating operator is a bounded operator A such that Ax = y. In this article, we investigate self-adjoint interpolation problems for vectors in a tridiagonal algebra: Let AlgL be a tridiagonal algebra on a separable complex Hilbert space H and let $x=(x_i)$ and $y=(y_i)$ be vectors in H.Then the following are equivalent: (1) There exists a self-adjoint operator $A=(a_ij)$ in AlgL such that Ax = y. (2) There is a bounded real sequence {$a_n$} such that $y_i=a_ix_i$ for $i{\in}N$.